SignalR 在强制页面刷新后更新通知
SignalR updates notification after a forced page refresh
我在 ASP.NET 核心 MVC 项目中使用 signalR 向用户推送通知。
我研究了类似的问题,但它的解决方案并没有解决我的问题。我使用了以下 Javascript/jQuery 参考资料:
<script type="text/javascript" src="../../js/UserPage/jquery-3.6.0.min.js"></script>
<script src="~/microsoft/signalr/dist/browser/signalr.js"></script>
<script src="~/js/message.js"></script>
message.js如下:
var connection = new signalR.HubConnectionBuilder().withUrl("/Home/Messages").withAutomaticReconnect().build();
connection.start();
if (document.getElementById("sendBtn") != null) {
document.getElementById("sendBtn").addEventListener("click", function () {
var costCenter = $("#cost-center").val();
connection.invoke("SendMessage", costCenter).catch(function (err) {
return console.error(err);
});
});
}
集线器代码:
public class MessageHub : Hub
{
//Dependency injections
private readonly IUserRepository _userRepository;
private readonly ICostCenterRepository _costcenterRepository;
private readonly IHttpContextAccessor _httpContext;
public MessageHub(IUserRepository userRepository, ICostCenterRepository costcenterRepository, IHttpContextAccessor httpContext)
{
_userRepository = userRepository;
_costcenterRepository = costcenterRepository;
_httpContext = httpContext;
}
public async Task SendMessage(string costCenter)
{
var HttpContext = _httpContext.HttpContext;
string userId = _userRepository.GetUserIdByCostCenter(costCenter).ToString();
string sender = HttpContext.Session.GetString("department");
await Clients.User(userId).SendAsync("ReceiveMessage", sender);
}
}
而且,javascript主页中的代码是:
<script>
$(document).ready(function(){
connection.on("ReceiveMessage", function (param) {
if($('#badge-count').length){
var currentMessageNum = parseInt($('#badge-count').text());
$('#badge-count').text(currentMessageNum + 1);
$('.main-msg-list').prepend('<li><a class="dropdown-item message-item" style="font-family: vazir !important" asp-controller="Messages" asp-action="Index" href="" id="msg-'+ currentMessageNum + 1 +'">پیام جدید از '+ param +'</a></li>');
}else{
$('#badge-count').text('1');
}
});
});
</script>
问题是通知在强制刷新后更新。之后,通知工作正常并立即更新。我该如何解决?
我通过对 Hub 代码进行一些更改解决了这个问题:
[Authorize]
public class MessageHub : Hub
{
//Dependancy injections
private readonly IUserRepository _userRepository;
private readonly ICostCenterRepository _costcenterRepository;
private readonly IHttpContextAccessor _httpContext;
public MessageHub(IUserRepository userRepository, ICostCenterRepository costcenterRepository, IHttpContextAccessor httpContext)
{
_userRepository = userRepository;
_costcenterRepository = costcenterRepository;
_httpContext = httpContext;
}
//define a dictionary to store the userid.
private static Dictionary<string, List<string>> NtoIdMappingTable = new Dictionary<string, List<string>>();
public override async Task OnConnectedAsync()
{
var username = Context.User.Identity.Name;
var userId = Context.UserIdentifier;
List<string> userIds;
//store the userid to the list.
if (!NtoIdMappingTable.TryGetValue(username, out userIds))
{
userIds = new List<string>();
userIds.Add(userId);
NtoIdMappingTable.Add(username, userIds);
}
else
{
userIds.Add(userId);
}
await base.OnConnectedAsync();
}
public override async Task OnDisconnectedAsync(Exception exception)
{
var username = Context.User.Identity.Name;
//remove userid from the List
if (NtoIdMappingTable.ContainsKey(username))
{
NtoIdMappingTable.Remove(username);
}
await base.OnDisconnectedAsync(exception);
}
public async Task SendMessage(string costCenter)
{
var HttpContext = _httpContext.HttpContext;
string username = _userRepository.GetUsernameByCostCenter(costCenter).ToString();
var userId = NtoIdMappingTable.GetValueOrDefault(username);
string sender = HttpContext.Session.GetString("department");
await Clients.User(userId.FirstOrDefault()).SendAsync("ReceiveMessage", sender);
}
}
我在 ASP.NET 核心 MVC 项目中使用 signalR 向用户推送通知。
我研究了类似的问题
<script type="text/javascript" src="../../js/UserPage/jquery-3.6.0.min.js"></script>
<script src="~/microsoft/signalr/dist/browser/signalr.js"></script>
<script src="~/js/message.js"></script>
message.js如下:
var connection = new signalR.HubConnectionBuilder().withUrl("/Home/Messages").withAutomaticReconnect().build();
connection.start();
if (document.getElementById("sendBtn") != null) {
document.getElementById("sendBtn").addEventListener("click", function () {
var costCenter = $("#cost-center").val();
connection.invoke("SendMessage", costCenter).catch(function (err) {
return console.error(err);
});
});
}
集线器代码:
public class MessageHub : Hub
{
//Dependency injections
private readonly IUserRepository _userRepository;
private readonly ICostCenterRepository _costcenterRepository;
private readonly IHttpContextAccessor _httpContext;
public MessageHub(IUserRepository userRepository, ICostCenterRepository costcenterRepository, IHttpContextAccessor httpContext)
{
_userRepository = userRepository;
_costcenterRepository = costcenterRepository;
_httpContext = httpContext;
}
public async Task SendMessage(string costCenter)
{
var HttpContext = _httpContext.HttpContext;
string userId = _userRepository.GetUserIdByCostCenter(costCenter).ToString();
string sender = HttpContext.Session.GetString("department");
await Clients.User(userId).SendAsync("ReceiveMessage", sender);
}
}
而且,javascript主页中的代码是:
<script>
$(document).ready(function(){
connection.on("ReceiveMessage", function (param) {
if($('#badge-count').length){
var currentMessageNum = parseInt($('#badge-count').text());
$('#badge-count').text(currentMessageNum + 1);
$('.main-msg-list').prepend('<li><a class="dropdown-item message-item" style="font-family: vazir !important" asp-controller="Messages" asp-action="Index" href="" id="msg-'+ currentMessageNum + 1 +'">پیام جدید از '+ param +'</a></li>');
}else{
$('#badge-count').text('1');
}
});
});
</script>
问题是通知在强制刷新后更新。之后,通知工作正常并立即更新。我该如何解决?
我通过对 Hub 代码进行一些更改解决了这个问题:
[Authorize]
public class MessageHub : Hub
{
//Dependancy injections
private readonly IUserRepository _userRepository;
private readonly ICostCenterRepository _costcenterRepository;
private readonly IHttpContextAccessor _httpContext;
public MessageHub(IUserRepository userRepository, ICostCenterRepository costcenterRepository, IHttpContextAccessor httpContext)
{
_userRepository = userRepository;
_costcenterRepository = costcenterRepository;
_httpContext = httpContext;
}
//define a dictionary to store the userid.
private static Dictionary<string, List<string>> NtoIdMappingTable = new Dictionary<string, List<string>>();
public override async Task OnConnectedAsync()
{
var username = Context.User.Identity.Name;
var userId = Context.UserIdentifier;
List<string> userIds;
//store the userid to the list.
if (!NtoIdMappingTable.TryGetValue(username, out userIds))
{
userIds = new List<string>();
userIds.Add(userId);
NtoIdMappingTable.Add(username, userIds);
}
else
{
userIds.Add(userId);
}
await base.OnConnectedAsync();
}
public override async Task OnDisconnectedAsync(Exception exception)
{
var username = Context.User.Identity.Name;
//remove userid from the List
if (NtoIdMappingTable.ContainsKey(username))
{
NtoIdMappingTable.Remove(username);
}
await base.OnDisconnectedAsync(exception);
}
public async Task SendMessage(string costCenter)
{
var HttpContext = _httpContext.HttpContext;
string username = _userRepository.GetUsernameByCostCenter(costCenter).ToString();
var userId = NtoIdMappingTable.GetValueOrDefault(username);
string sender = HttpContext.Session.GetString("department");
await Clients.User(userId.FirstOrDefault()).SendAsync("ReceiveMessage", sender);
}
}